# Plant Diseases

## 1st Edition

### Epidemics and Control

**Authors:**J. E. Van Der Plank

**eBook ISBN:**9781483262130

**Imprint:**Academic Press

**Published Date:**1st January 1964

**Page Count:**366

## Description

Plant Diseases: Epidemics and Control provides a description of the methods of epidemiological analysis based on infection rates and the relation between the amount of inoculum and the amount of disease it produces. The book shows how to study the increase of pathogen populations and the epidemiological strategy to be adopted to control the epidemic of plant diseases. The text covers the calculation of the logarithmic increase of disease; use of epidemiology in the study of control; forms of sanitation; the use of resistant plant varieties; and the design of field experiments. Plant pathologists and breeders, agriculturists, horticulturists, research workers, teachers, and students will find the text invaluable.

## Table of Contents

Contents

Preface

Chapter 1 The Control of Plant Disease Studied as Part of Epidemiology

1.1. The Population of Pathogens

1.2. Epidemics and Biological Warfare

1.3. The Language of Epidemiology. Some Expressions

1.4. A Suggested Order of Reading the Chapters

1.5. The Spread of Disease and Its Bearing on the Technique of Field Experiments

Chapter 2 About Interest on Money. Logarithmic Increase

Summary

2.1. Interest is Proportional to Initial Capital

2.2. Interest per Cent and Interest per Unit

2.3. Simple Interest

2.4. Discontinuous Compound Interest

2.5. Continuous Compound Interest

2.6. Continuous Compound Interest Seen in Another Way

2.7. Equivalent Rates of Continuous and Discontinuous Compound Interest

2.8. Variable Rates of Continuous Compound Interest

2.9. Consistent Units of Time

2.10. Natural Logarithms

2.11. Logarithmic Increase

Exercises

Chapter 3 The Logarithmic and the Apparent Infection Rates

Summary

3.1. Statement of the General Problem of This Book

3.2. The Intermittent Increase of Disease

3.3. The Percentage and the Proportion of Disease

3.4. Logarithmic Increase of Disease and Increase That Is Not Logarithmic

3.5. The Meaning of Infection Rates

3.6. The Words, "per Unit," Again

Exercises

Chapter 4 How to Plot the Progress of an Epidemic

Summary

4.1. The Increase of Disease with Time

4.2. Two Ways in Which Disease Can Increase with Time."Compound Interest Disease'* and "Simple Interest Disease"

4.3. Increase of Disease by Multiplication. "Compound Interest Disease"

4.4. The Increase of Disease without Multiplication. "Simple Interest Disease"

4.5. The Correction Factor (l — x)

4.6. The Reason for Using Log [1/(1 - x)] When There is No Multiplication

Exercises

Epilogue

Chapter 5 The Basic Infection Rate

Summary

5.1. The Basic Infection Rate and the Latent Period

5.2. The Incubation Period

5.3. Some Biological Meanings

5.4. The Early Stages of Artificially Induced Epidemics of Stem Rust of Wheat

5.5. The Relation between r and R

5.6. How R Changes as an Epidemic Progresses

5.7. The Relation between r1 and R

5.8. The Products pr1, pr, and pR

5.9. The Limit to the Explosiveness of an Epidemic

5.10. A Discontinuous Infection Model

5.11. Period of Infection is Reduced to a Point Each Year and p is 1 Year

Exercises

Chapter 6 The Latent Period

Summary 59

6.1. Logarithmic Increase of Infection with p and R Constant

6.2. The Variation of n with Time, with p and R Constant

6.3. The Variation of r{ at an Average Value over an Interval of Time

6.4. The Effect of a Prolonged Period of Inoculation on the Variation of r1

6.5. The Effect of Variation of the Latent Period p on the Variation of r1

6.6. A Wider Interpretation of r1

6.7. The Error from Using a Constant Mean Value p in Eq. (5.7) Instead of a Constant Value p

6.8. Increase of Infection beyond the Logarithmic Phase with p and R Constant

6.9. The Estimation of n after the Logarithmic Stage of an Epidemic

6.10. Three Arbitrary Stages in an Epidemic

Exercise

Chapter 7 Average Values of Infection Rates. Increase of Populations of Lesions and of Foci. Independent Action of Propagules

Summary

7.1. The Relative Infection Rate as an Average

7.2. The Logarithmic Infection Rate

7.3. The Growth of an Individual Lesion in Relation to the Growth of a Population of Lesions

7.4. The Growth of Foci

7.5. The Spread of Pathogens in Relation to the Focal Pattern

7.6. The Growth of an Individual Focus in Relation to the Growth of a Population of Foci

7.7. The Mass Increase of Foci

7.8. Massed Foci of Potato Blight. The Epidemic S

7.9. The Independent Action of Propagules. The General Problem

7.10. The Independent Action of Propagules. Puccinia graminis. Phytophthora infestons, and Some Other Pathogens

Chapter 8 Corrected Infection Rates

Summary

8.1. Correction of n and r for the Growth of the Host Plants

8.2. Correction for Removals

8.3. Relation between the Corrected Basic Infection Rate Re and r

8.4. Balance in Epidemics

8.5. Relation between Rc and r1

8.6. A Threshold Theorem

8.7. The Threshold Theorem and Control of Disease by Fungicides

8.8. The Threshold in Epidemics of Two Systemic Diseases

8.9. Looking Back

Exercises and Examples

Chapter 9 Stochastic Methods in Epidemiology

Summary

9.1. Transforming Proportions of Disease

9.2. Sampling Errors of Estimates of Infection Rates

9.3. Deterministic and Probability Methods in Epidemiology

9.4. Multiple Infections with Systemic Disease

9.5. The Overlapping of Local Lesions

9.6. The Influence of Numbers

9.7. Comparisons with Medical Epidemiology

Chapter 10 A Guide to the Chapters on Control of Disease

10.1. The General Proposition

10.2. Control Measures That Reduce xo: Sanitation, Vertical Resistance, and Chemical Eradication

10.3. Control Measures That Reduce r: Horizontal Resistance and Protectant Fungicides

Chapter 11 Sanitation with Special Reference to Potato Blight

Summary

11.1. A Definition of Sanitation

11.2. How the Infection Rate Affects the Benefit from Sanitation

11.3. The Effect of the Sanitation Ratio

11.4. The Effect of Sanitation on Disease after the Logarithmic Phase

11.5. The Use of Eqs. (11.1) and (11.2) when Disease Is in Foci

11.6. Phytophthora infestans from Potato Cull Piles

11.7. Focal Outbreaks and General Epidemics of Potato Blight

11.8. The Change from Focal Outbreaks to General Epidemics

11.9. The Delay of the General Epidemic as a Result of Destroying Cull Piles

11.10. Cull Piles and Blight Forecasts

11.11. The Increase in Yield as a Result of Sanitation

Chapter 12 Sanitation with Special Reference to Wheat Stem Rust

Summary

12.1. Potato Blight and Wheat Stem Rust Contrasted and Compared

12.2. Stem Rust and Barberry Eradication

12.3. Focal Outbreaks and General Epidemics of Wheat Stem Rust

12.4. Barberry Eradication and Wheat Stem Rust in Northwestern Europe

12.5. The Relation between Sanitation and the Percentage of Stem Rust in Ripe Fields

12.6. The Reduction by Sanitation of Loss in Yield

12.7. The Relation between Loss of Yield and the Area under Stem Rust Progress Curve

12.8. The Infection Rate in Relation to Benefits Gained from Sanitation

12.9. Potato Blight and Wheat Stem Rust Compared Again

Chapter 13 Sanitation and Two Systemic Diseases. Sanitation when Other Things Are Not Equal

Summary

13.1. Common Bunt of Wheat and Fuearium Wilt of Tomatoes

13.2. The Relation between the Number of Spores and Infection of Wheat by Bunt

13.3. The Relation between the Number of Spores and Infection of Tomatoes with Fusarium Wilt

13.4. The Effect of Sanitation on Disease of the "Simple Interest" Type

13.5. The Benefit of Reducing Systemic Disease by Sanitation

13.6. Dependability of Sanitation as a Method of Disease Control in Relation to rt

13.7. Sanitation in Relation to the Absolute Amount of Initial Inoculum

13.8. A Comparison between "Simple Interest" and "Compound Interest" Disease in Relation to Sanitation

13.9. Two Kinds of Initial Inoculum

Exercise

Chapter 14 Vertical and Horizontal Resistance against Potato Blight

Summary

14.1. The Relation between Races of Phytophthora infestons and Resistance Genes in the Potato

14.2. The Mutability of Races of Phytophthora infestons

14.3. Vertical and Horizontal Resistance

14.4. The Unimportance of Vertical Resistance in Varieties without R Genes

14.5. The Distribution of Races

14.6. The Effect of Popularity on the Behavior of R-Types toward Blight

14.7. The Place of Vertical and Horizontal Resistance in Epidemiology

14.8. Analysis of Kirste's Findings: the Effect of Vertical Resistance

14.9. Analysis of Kirste's Findings: the Effect of Horizontal Resistance

14.10. Other Evidence for a Difference in Horizontal Resistance

14.11. Some Published Assessments of Blight Resistance

14.12. The Vertifolia Effect

14.13. Blight on Solanum demissum

14.14. Blight on Mixtures of Clones

14.15. What Vertical Resistance Implies

14.16. The Manifestations of Horizontal Resistance

14.17. The Quantitative Determination of Horizontal Resistance when There Is Also Vertical Resistance

14.18. The Deficiency of Horizontal Resistance in Commercial Varieties

14.19. Breeding Potato Varieties for Resistance to Blight

Chapter 15 A Note on the History of Stem Rust Epidemics in Spring Wheat in North America

Summary

15.1. The Problem in the Spring Wheat Area of North America

15.2. Some Early History

15.3. Waldron's Evidence

15.4. The Evidence of Stakman and Fletcher

15.5. The First Class Epidemics

15.6. Some Conclusions

Chapter 16 Plant Disease in Biological Warfare

Summary

16.1 Epidemics as Explosives

16.2. Vertically Resistant Crops as a Target

16.3. Wheat Stem Rust as an Example

16.4. Stem Rust Races that Can Overcome Vertical Resistance

16.5. Weather Adverse to Epidemics

16.6. Horizontal Resistance for Defense

16.7. Horizontal Resistance to Stem Rust

16.8. Quantitative Interpretation of the Evidence

16.9. The Transition

Exercise

Chapter 17 The Bases of Vertical Resistance

Summary

17.1. Introduction

17.2. The Different Response of Horizontal and Vertical Resistance to Diversity of Varieties

17.3. The Dependence of Vertical Resistance on Varietal Diversity

17.4. A Reason Why Vertical Resistance Is Commonly Chosen to Protect Varieties

17.5. Diversity and Novelty

17.6. The Fitness of Simple Races on Simple Varieties

17.7. Evidence for Stabilizing Selection of Simple Races of Puccinia graminie tritici

17.8. Vertical Resistance without Novelty

17.9. Natural Stability in Vertical Resistance

Chapter 18 General Resistance against Disease

Summary

18.1. General Resistance

18.2. Results of Troutman and Fulton and of Holmes

18.3. The Commonness of Resistance

18.4. The Need to Stress Affinities

18.5. The Search for General Resistance

Chapter 19 The Choice of Type of Resistance

Summary 240

19.1. The Aims of Plant Breeding

19.2. The Difficulty about Generalizing

19.3. The Usual Preference for Vertical Resistance

19.4. The Case for Vertical Resistance

19.5. The Possibility of Improving Vertical Resistance

19.6. The Choice of Horizontal Resistance when There Has Been a Record of Varietal Change

19.7. The Choice of Horizontal Resistance when rt Is High

19.8. The Choice of Horizontal Resistance when There Is Danger of a Vertifolia Effect

19.9. The Choice of Horizontal Resistance when There Is Danger of Biological Warfare

19.10. The Choice of Horizontal Resistance when Fungicides Are Used

Chapter 20 The Quantitative Effect of Horizontal Resistance

Summary

20.1. The Components of Horizontal Resistance

20.2. Changing the Basic Infection Rate

20.3. A Return to Tables 16.3 and 16.4

20.4. Relative Insensitivity of the Apparent Infection Rate to Change when the Basic Rate Is High

20.5. The Effect of a Change of the Latent Period on the Apparent Infection Rate

20.6. The Effect of Removals on the Apparent Infection Rate

20.7. The Effect of Resistance

20.8. The General Simplification

Chapter 21 Control of Disease by Fungicides

Summary

21.1. The Fungicide Square

21.2. Laboratory and Glasshouse Experiments with Phytophthora infestans

21.3. The Performance of Fungicides against Potato Blight in the Field

21.4. Citrus Black Spot and Apple Scab

21.5. The Calculated Effect of Horizontal Resistance or Adverse Climate on the Degree of Fungicidal Activity Needed

21.6. Other Calculated Effects

21.7. Variable Results with Fungicides and the Need for Recording

21.8. The Timing of Application of Protectant Fungicides

21.9. Eradicant Fungicides in Relation to the Infection Rate

21.10. The Fungicide Frontier

21.11. The Forgotten Factor

Chapter 22 How Disease Spreads as It Increases

Summary

22.1. Increase and Spread of Disease

22.2. The Spread of Wheat Stem Rust

22.3. The Spread of Potato Blight

22.4. Wheat Stem Rust and Potato Blight Contrasted Again

22.5. The Flattening of Gradients

22.6. Increasing Disease and Increasing Scale of Distance of Spread

22.7. The Behavior of Populations of Pathogens and of Individual Propagules; the Disease Triangle

Chapter 23 The Cryptic Error in Field Experiments

Summary

23.1. Errors of Representation in Results from Plots in a Field Experiment

23.2. An Experiment with Tomato Fruit Diseases

23.3. An Experiment with Leaf Rust of Wheat

23.4. An Experiment with Stem Rust of Wheat and Rye

23.5. The Deposition of Spores

23.6. Some Calculations for Potato Blight

23.7. Large's Observations on Potato Blight

23.8. The Inadequacy of Guard Rows in Conventional Designs

23.9. The Gradient Fallacy

23.10. The Gradient Fallacy Illustrated

23.11. The Cryptic Error

23.12. Where the Onus of Proof Lies

23.13. The Error when Unsprayed Plots Represent Unsprayed Fields

23.14. The Loss of Air-borne Spores from Plots and Fields

23.15. The Movement of Spores between Plots within an Experimental Area

23.16. The Effect of the Size of Plot

23.17. The Effect of Shape of Plot

23.18. Interference between Plots

23.19. Different Types of Experiment

23.20. The Screening and Ranking of Fungicides in the Field

23.21. Quantitative Comparison of Fungicide Treatments

23.22. Experiments with Plots That Differ Greatly in Disease

23.23. Variety Trial

23.24. The Conservative Error Theory

23.25. The Field Side of the Story

Appendix

References

Author Index

Subject Index

## Details

- No. of pages:
- 366

- Language:
- English

- Copyright:
- © Academic Press 1963

- Published:
- 1st January 1964

- Imprint:
- Academic Press

- eBook ISBN:
- 9781483262130